/*
Copyright (C) 1999 CERN - European Organization for Nuclear Research.
Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose 
is hereby granted without fee, provided that the above copyright notice appear in all copies and 
that both that copyright notice and this permission notice appear in supporting documentation. 
CERN makes no representations about the suitability of this software for any purpose. 
It is provided "as is" without expressed or implied warranty.
 */
package cern.colt.matrix.tlong.impl;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

import cern.colt.matrix.tlong.LongMatrix1D;
import cern.colt.matrix.tlong.LongMatrix2D;
import edu.emory.mathcs.utils.pc.ConcurrencyUtils;

/**
 * Diagonal 2-d matrix holding <tt>long</tt> elements. First see the <a
 * href="package-summary.html">package summary</a> and javadoc <a
 * href="package-tree.html">tree view</a> to get the broad picture.
 * <p>
 * 
 * @author Piotr Wendykier (piotr.wendykier@gmail.com)
 */
public class DiagonalLongMatrix2D extends WrapperLongMatrix2D {
    private static final long serialVersionUID = 1L;

    /*
     * The non zero elements of the matrix.
     */
    protected long[] elements;

    /*
     * Length of the diagonal
     */
    protected int dlength;

    /*
     * An m-by-n matrix A has m+n-1 diagonals. Since the DiagonalLongMatrix2D can have only one
     * diagonal, dindex is a value from interval [-m+1, n-1] that denotes which diagonal is stored.
     */
    protected int dindex;

    /**
     * Constructs a matrix with a copy of the given values. <tt>values</tt> is
     * required to have the form <tt>values[row][column]</tt> and have exactly
     * the same number of columns in every row. Only the values on the main
     * diagonal, i.e. values[i][i] are used.
     * <p>
     * The values are copied. So subsequent changes in <tt>values</tt> are not
     * reflected in the matrix, and vice-versa.
     * 
     * @param values
     *            The values to be filled into the new matrix.
     * @param dindex
     *            index of the diagonal.
     * @throws IllegalArgumentException
     *             if
     * 
     *             <tt>for any 1 &lt;= row &lt; values.length: values[row].length != values[row-1].length || index < -rows+1 || index > columns - 1</tt>
     *             .
     */
    public DiagonalLongMatrix2D(long[][] values, int dindex) {
        this(values.length, values.length == 0 ? 0 : values[0].length, dindex);
        assign(values);
    }

    /**
     * Constructs a matrix with a given number of rows and columns. All entries
     * are initially <tt>0</tt>.
     * 
     * @param rows
     *            the number of rows the matrix shall have.
     * @param columns
     *            the number of columns the matrix shall have.
     * @param dindex
     *            index of the diagonal.
     * @throws IllegalArgumentException
     *             if <tt>size<0 (long)size > Integer.MAX_VALUE</tt>.
     */
    public DiagonalLongMatrix2D(int rows, int columns, int dindex) {
        super(null);
        try {
            setUp(rows, columns);
        } catch (IllegalArgumentException exc) { // we can hold rows*columns>Integer.MAX_VALUE cells !
            if (!"matrix too large".equals(exc.getMessage()))
                throw exc;
        }
        if ((dindex < -rows + 1) || (dindex > columns - 1)) {
            throw new IllegalArgumentException("index is out of bounds");
        } else {
            this.dindex = dindex;
        }
        if (dindex == 0) {
            dlength = Math.min(rows, columns);
        } else if (dindex > 0) {
            if (rows >= columns) {
                dlength = columns - dindex;
            } else {
                int diff = columns - rows;
                if (dindex <= diff) {
                    dlength = rows;
                } else {
                    dlength = rows - (dindex - diff);
                }
            }
        } else {
            if (rows >= columns) {
                int diff = rows - columns;
                if (-dindex <= diff) {
                    dlength = columns;
                } else {
                    dlength = columns + dindex + diff;
                }
            } else {
                dlength = rows + dindex;
            }
        }
        elements = new long[dlength];
    }

    public LongMatrix2D assign(final cern.colt.function.tlong.LongFunction function) {
        if (function instanceof cern.jet.math.tlong.LongMult) { // x[i] = mult*x[i]
            final long alpha = ((cern.jet.math.tlong.LongMult) function).multiplicator;
            if (alpha == 1)
                return this;
            if (alpha == 0)
                return assign(0);
            if (alpha != alpha)
                return assign(alpha); // the funny definition of isNaN(). This should better not happen.
            for (int j = dlength; --j >= 0;) {
                elements[j] *= alpha;
            }
        } else {
            for (int j = dlength; --j >= 0;) {
                elements[j] = function.apply(elements[j]);
            }
        }
        return this;
    }

    public LongMatrix2D assign(long value) {
        for (int i = dlength; --i >= 0;)
            elements[i] = value;
        return this;
    }

    public LongMatrix2D assign(final long[] values) {
        if (values.length != dlength)
            throw new IllegalArgumentException("Must have same length: length=" + values.length + " dlength=" + dlength);
        int nthreads = ConcurrencyUtils.getNumberOfThreads();
        if ((nthreads > 1) && (dlength >= ConcurrencyUtils.getThreadsBeginN_2D())) {
            nthreads = Math.min(nthreads, dlength);
            Future<?>[] futures = new Future[nthreads];
            int k = dlength / nthreads;
            for (int j = 0; j < nthreads; j++) {
                final int firstRow = j * k;
                final int lastRow = (j == nthreads - 1) ? dlength : firstRow + k;
                futures[j] = ConcurrencyUtils.submit(new Runnable() {

                    public void run() {
                        for (int r = firstRow; r < lastRow; r++) {
                            elements[r] = values[r];
                        }
                    }
                });
            }
            ConcurrencyUtils.waitForCompletion(futures);
        } else {
            for (int r = dlength; --r >= 0;) {
                elements[r] = values[r];
            }
        }
        return this;
    }

    public LongMatrix2D assign(final long[][] values) {
        if (values.length != rows)
            throw new IllegalArgumentException("Must have same number of rows: rows=" + values.length + "rows()="
                    + rows());
        int r, c;
        if (dindex >= 0) {
            r = 0;
            c = dindex;
        } else {
            r = -dindex;
            c = 0;
        }
        for (int i = 0; i < dlength; i++) {
            if (values[i].length != columns) {
                throw new IllegalArgumentException("Must have same number of columns in every row: columns="
                        + values[r].length + "columns()=" + columns());
            }
            elements[i] = values[r++][c++];
        }
        return this;
    }

    public LongMatrix2D assign(LongMatrix2D source) {
        // overriden for performance only
        if (source == this)
            return this; // nothing to do
        checkShape(source);

        if (source instanceof DiagonalLongMatrix2D) {
            DiagonalLongMatrix2D other = (DiagonalLongMatrix2D) source;
            if ((dindex != other.dindex) || (dlength != other.dlength)) {
                throw new IllegalArgumentException("source is DiagonalLongMatrix2D with different diagonal stored.");
            }
            // quickest
            System.arraycopy(other.elements, 0, this.elements, 0, this.elements.length);
            return this;
        } else {
            return super.assign(source);
        }
    }

    public LongMatrix2D assign(final LongMatrix2D y, final cern.colt.function.tlong.LongLongFunction function) {
        checkShape(y);
        if (y instanceof DiagonalLongMatrix2D) {
            DiagonalLongMatrix2D other = (DiagonalLongMatrix2D) y;
            if ((dindex != other.dindex) || (dlength != other.dlength)) {
                throw new IllegalArgumentException("y is DiagonalLongMatrix2D with different diagonal stored.");
            }
            if (function instanceof cern.jet.math.tlong.LongPlusMultSecond) { // x[i] = x[i] + alpha*y[i]
                final long alpha = ((cern.jet.math.tlong.LongPlusMultSecond) function).multiplicator;
                if (alpha == 0) {
                    return this; // nothing to do
                }
            }
            final long[] otherElements = other.elements;
            int nthreads = ConcurrencyUtils.getNumberOfThreads();
            if ((nthreads > 1) && (dlength >= ConcurrencyUtils.getThreadsBeginN_2D())) {
                nthreads = Math.min(nthreads, dlength);
                Future<?>[] futures = new Future[nthreads];
                int k = dlength / nthreads;
                for (int j = 0; j < nthreads; j++) {
                    final int startrow = j * k;
                    final int stoprow;
                    if (j == nthreads - 1) {
                        stoprow = dlength;
                    } else {
                        stoprow = startrow + k;
                    }
                    futures[j] = ConcurrencyUtils.submit(new Runnable() {

                        public void run() {
                            if (function instanceof cern.jet.math.tlong.LongPlusMultSecond) { // x[i] = x[i] + alpha*y[i]
                                final long alpha = ((cern.jet.math.tlong.LongPlusMultSecond) function).multiplicator;
                                if (alpha == 1) {
                                    for (int j = startrow; j < stoprow; j++) {
                                        elements[j] += otherElements[j];
                                    }
                                } else {
                                    for (int j = startrow; j < stoprow; j++) {
                                        elements[j] = elements[j] + alpha * otherElements[j];
                                    }
                                }
                            } else if (function == cern.jet.math.tlong.LongFunctions.mult) { // x[i] = x[i] * y[i]
                                for (int j = startrow; j < stoprow; j++) {
                                    elements[j] = elements[j] * otherElements[j];
                                }
                            } else if (function == cern.jet.math.tlong.LongFunctions.div) { // x[i] = x[i] /  y[i]
                                for (int j = startrow; j < stoprow; j++) {
                                    elements[j] = elements[j] / otherElements[j];
                                }
                            } else {
                                for (int j = startrow; j < stoprow; j++) {
                                    elements[j] = function.apply(elements[j], otherElements[j]);
                                }
                            }
                        }
                    });
                }
                ConcurrencyUtils.waitForCompletion(futures);
            } else {
                if (function instanceof cern.jet.math.tlong.LongPlusMultSecond) { // x[i] = x[i] + alpha*y[i]
                    final long alpha = ((cern.jet.math.tlong.LongPlusMultSecond) function).multiplicator;
                    if (alpha == 1) {
                        for (int j = dlength; --j >= 0;) {
                            elements[j] += otherElements[j];
                        }
                    } else {
                        for (int j = dlength; --j >= 0;) {
                            elements[j] = elements[j] + alpha * otherElements[j];
                        }
                    }
                } else if (function == cern.jet.math.tlong.LongFunctions.mult) { // x[i] = x[i] * y[i]
                    for (int j = dlength; --j >= 0;) {
                        elements[j] = elements[j] * otherElements[j];
                    }
                } else if (function == cern.jet.math.tlong.LongFunctions.div) { // x[i] = x[i] /  y[i]
                    for (int j = dlength; --j >= 0;) {
                        elements[j] = elements[j] / otherElements[j];
                    }
                } else {
                    for (int j = dlength; --j >= 0;) {
                        elements[j] = function.apply(elements[j], otherElements[j]);
                    }
                }
            }
            return this;
        } else {
            return super.assign(y, function);
        }
    }

    public int cardinality() {
        int cardinality = 0;
        int nthreads = ConcurrencyUtils.getNumberOfThreads();
        if ((nthreads > 1) && (dlength >= ConcurrencyUtils.getThreadsBeginN_2D())) {
            nthreads = Math.min(nthreads, dlength);
            Future<?>[] futures = new Future[nthreads];
            Integer[] results = new Integer[nthreads];
            int k = dlength / nthreads;
            for (int j = 0; j < nthreads; j++) {
                final int firstRow = j * k;
                final int lastRow = (j == nthreads - 1) ? dlength : firstRow + k;
                futures[j] = ConcurrencyUtils.submit(new Callable<Integer>() {
                    public Integer call() throws Exception {
                        int cardinality = 0;
                        for (int r = firstRow; r < lastRow; r++) {
                            if (elements[r] != 0)
                                cardinality++;
                        }
                        return cardinality;
                    }
                });
            }
            try {
                for (int j = 0; j < nthreads; j++) {
                    results[j] = (Integer) futures[j].get();
                }
                cardinality = results[0];
                for (int j = 1; j < nthreads; j++) {
                    cardinality += results[j];
                }
            } catch (ExecutionException ex) {
                ex.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } else {
            for (int r = 0; r < dlength; r++) {
                if (elements[r] != 0)
                    cardinality++;
            }
        }
        return cardinality;
    }

    public long[] elements() {
        return elements;
    }

    public boolean equals(long value) {
        for (int r = 0; r < dlength; r++) {
            long x = elements[r];
            long diff = value - x;
            if (diff != 0) {
                return false;
            }
        }
        return true;
    }

    public boolean equals(Object obj) {
        if (obj instanceof DiagonalLongMatrix2D) {
            DiagonalLongMatrix2D other = (DiagonalLongMatrix2D) obj;
            if (this == obj)
                return true;
            if (!(this != null && obj != null))
                return false;
            final int rows = this.rows();
            final int columns = this.columns();
            if (columns != other.columns() || rows != other.rows())
                return false;
            if ((dindex != other.dindex) || (dlength != other.dlength)) {
                return false;
            }
            long[] otherElements = other.elements;
            for (int r = 0; r < dlength; r++) {
                long x = elements[r];
                long value = otherElements[r];
                long diff = value - x;
                if (diff != 0) {
                    return false;
                }
            }
            return true;
        } else {
            return super.equals(obj);
        }
    }

    public LongMatrix2D forEachNonZero(final cern.colt.function.tlong.IntIntLongFunction function) {
        for (int j = dlength; --j >= 0;) {
            long value = elements[j];
            if (value != 0) {
                elements[j] = function.apply(j, j, value);
            }
        }
        return this;
    }

    /**
     * Returns the length of the diagonal
     * 
     * @return the length of the diagonal
     */
    public int diagonalLength() {
        return dlength;
    }

    /**
     * Returns the index of the diagonal
     * 
     * @return the index of the diagonal
     */
    public int diagonalIndex() {
        return dindex;
    }

    public long[] getMaxLocation() {
        int location = 0;
        long maxValue = 0;
        int nthreads = ConcurrencyUtils.getNumberOfThreads();
        if ((nthreads > 1) && (dlength >= ConcurrencyUtils.getThreadsBeginN_2D())) {
            nthreads = Math.min(nthreads, dlength);
            Future<?>[] futures = new Future[nthreads];
            long[][] results = new long[nthreads][2];
            int k = dlength / nthreads;
            for (int j = 0; j < nthreads; j++) {
                final int firstRow = j * k;
                final int lastRow = (j == nthreads - 1) ? dlength : firstRow + k;
                futures[j] = ConcurrencyUtils.submit(new Callable<long[]>() {
                    public long[] call() throws Exception {
                        int location = firstRow;
                        long maxValue = elements[location];
                        long elem;
                        for (int r = firstRow + 1; r < lastRow; r++) {
                            elem = elements[r];
                            if (maxValue < elem) {
                                maxValue = elem;
                                location = r;
                            }
                        }
                        return new long[] { maxValue, location, location };
                    }
                });
            }
            try {
                for (int j = 0; j < nthreads; j++) {
                    results[j] = (long[]) futures[j].get();
                }
                maxValue = results[0][0];
                location = (int) results[0][1];
                for (int j = 1; j < nthreads; j++) {
                    if (maxValue < results[j][0]) {
                        maxValue = results[j][0];
                        location = (int) results[j][1];
                    }
                }
            } catch (ExecutionException ex) {
                ex.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } else {
            maxValue = elements[0];
            long elem;
            for (int r = 1; r < dlength; r++) {
                elem = elements[r];
                if (maxValue < elem) {
                    maxValue = elem;
                    location = r;
                }
            }
        }
        int rowLocation;
        int columnLocation;
        if (dindex > 0) {
            rowLocation = location;
            columnLocation = location + dindex;
        } else if (dindex < 0) {
            rowLocation = location - dindex;
            columnLocation = location;
        } else {
            rowLocation = location;
            columnLocation = location;
        }
        return new long[] { maxValue, rowLocation, columnLocation };
    }

    public long[] getMinLocation() {
        int location = 0;
        long minValue = 0;
        int nthreads = ConcurrencyUtils.getNumberOfThreads();
        if ((nthreads > 1) && (dlength >= ConcurrencyUtils.getThreadsBeginN_2D())) {
            nthreads = Math.min(nthreads, dlength);
            Future<?>[] futures = new Future[nthreads];
            long[][] results = new long[nthreads][2];
            int k = dlength / nthreads;
            for (int j = 0; j < nthreads; j++) {
                final int firstRow = j * k;
                final int lastRow = (j == nthreads - 1) ? dlength : firstRow + k;
                futures[j] = ConcurrencyUtils.submit(new Callable<long[]>() {
                    public long[] call() throws Exception {
                        int location = firstRow;
                        long minValue = elements[location];
                        long elem;
                        for (int r = firstRow + 1; r < lastRow; r++) {
                            elem = elements[r];
                            if (minValue > elem) {
                                minValue = elem;
                                location = r;
                            }
                        }
                        return new long[] { minValue, location, location };
                    }
                });
            }
            try {
                for (int j = 0; j < nthreads; j++) {
                    results[j] = (long[]) futures[j].get();
                }
                minValue = results[0][0];
                location = (int) results[0][1];
                for (int j = 1; j < nthreads; j++) {
                    if (minValue > results[j][0]) {
                        minValue = results[j][0];
                        location = (int) results[j][1];
                    }
                }
            } catch (ExecutionException ex) {
                ex.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } else {
            minValue = elements[0];
            long elem;
            for (int r = 1; r < dlength; r++) {
                elem = elements[r];
                if (minValue > elem) {
                    minValue = elem;
                    location = r;
                }
            }
        }
        int rowLocation;
        int columnLocation;
        if (dindex > 0) {
            rowLocation = location;
            columnLocation = location + dindex;
        } else if (dindex < 0) {
            rowLocation = location - dindex;
            columnLocation = location;
        } else {
            rowLocation = location;
            columnLocation = location;
        }
        return new long[] { minValue, rowLocation, columnLocation };
    }

    public long getQuick(int row, int column) {
        if (dindex >= 0) {
            if (column < dindex) {
                return 0;
            } else {
                if ((row < dlength) && (row + dindex == column)) {
                    return elements[row];
                } else {
                    return 0;
                }
            }
        } else {
            if (row < -dindex) {
                return 0;
            } else {
                if ((column < dlength) && (row + dindex == column)) {
                    return elements[column];
                } else {
                    return 0;
                }
            }
        }
    }

    public LongMatrix2D like(int rows, int columns) {
        return new SparseLongMatrix2D(rows, columns);
    }

    public LongMatrix1D like1D(int size) {
        return new SparseLongMatrix1D(size);
    }

    public void setQuick(int row, int column, long value) {
        if (dindex >= 0) {
            if (column < dindex) {
                //do nothing
            } else {
                if ((row < dlength) && (row + dindex == column)) {
                    elements[row] = value;
                } else {
                    // do nothing
                }
            }
        } else {
            if (row < -dindex) {
                //do nothing
            } else {
                if ((column < dlength) && (row + dindex == column)) {
                    elements[column] = value;
                } else {
                    //do nothing;
                }
            }
        }
    }

    public LongMatrix1D zMult(LongMatrix1D y, LongMatrix1D z, long alpha, long beta, final boolean transposeA) {
        int rowsA = rows;
        int columnsA = columns;
        if (transposeA) {
            rowsA = columns;
            columnsA = rows;
        }

        boolean ignore = (z == null);
        if (z == null)
            z = new DenseLongMatrix1D(rowsA);

        if (!(this.isNoView && y instanceof DenseLongMatrix1D && z instanceof DenseLongMatrix1D)) {
            return super.zMult(y, z, alpha, beta, transposeA);
        }

        if (columnsA != y.size() || rowsA > z.size())
            throw new IllegalArgumentException("Incompatible args: "
                    + ((transposeA ? viewDice() : this).toStringShort()) + ", " + y.toStringShort() + ", "
                    + z.toStringShort());

        if ((!ignore) && ((beta) != 1))
            z.assign(cern.jet.math.tlong.LongFunctions.mult(beta));

        DenseLongMatrix1D zz = (DenseLongMatrix1D) z;
        final long[] elementsZ = zz.elements;
        final int strideZ = zz.stride();
        final int zeroZ = (int) z.index(0);

        DenseLongMatrix1D yy = (DenseLongMatrix1D) y;
        final long[] elementsY = yy.elements;
        final int strideY = yy.stride();
        final int zeroY = (int) y.index(0);

        if (elementsY == null || elementsZ == null)
            throw new InternalError();
        if (!transposeA) {
            if (dindex >= 0) {
                for (int i = dlength; --i >= 0;) {
                    elementsZ[zeroZ + strideZ * i] += alpha * elements[i] * elementsY[dindex + zeroY + strideY * i];
                }
            } else {
                for (int i = dlength; --i >= 0;) {
                    elementsZ[-dindex + zeroZ + strideZ * i] += alpha * elements[i] * elementsY[zeroY + strideY * i];
                }
            }
        } else {
            if (dindex >= 0) {
                for (int i = dlength; --i >= 0;) {
                    elementsZ[dindex + zeroZ + strideZ * i] += alpha * elements[i] * elementsY[zeroY + strideY * i];
                }
            } else {
                for (int i = dlength; --i >= 0;) {
                    elementsZ[zeroZ + strideZ * i] += alpha * elements[i] * elementsY[-dindex + zeroY + strideY * i];
                }
            }

        }
        return z;
    }

    protected LongMatrix2D getContent() {
        return this;
    }
}
